Any 2400 dpi printer?

  • Thread starter Thread starter Talal Itani
  • Start date Start date
Arthur Entlich said:
Although I was adducing black and white laser printers, when you state
you have an 8 bit CMYK printer, do you mean the printer is capable of
creating different densities of toner dot, and if so do you know how
that is done?
Click to expand...

Yes, some printers can create different densities of toner dot.
 
Mike Russell said:
Color laser uses a halftoning process, and does not deposit variable density
dots. AFAIK, dye-sub is the only process that actually does this.
Click to expand...

Incorrect.

Some color lasers use a halftoning process. Some (probably ones you've
never come across, because they cost more than $299) do not.
 
Arthur Entlich said:
Although I was adducing black and white laser printers, when you state
you have an 8 bit CMYK printer, do you mean the printer is capable of
creating different densities of toner dot, and if so do you know how
that is done?
Click to expand...
Its a two stage printer (CC 950 - the final version of the CLC 700),
with developer and toner, my understanding is that it can vary the
intensity of each of the four colours through 8 bits (256) levels,
presumably by adjusting the amount of developing that happens.

8 bit intensity still seems to be reserved to printers that costs
several thousand, but 4 bit intensity is I believe achievable round
about the $1000 mark now.

This greatly improves photo quality since there is little need for
dithering and so you don't get dot patterns.
 
I believe the question clearly related to your posting.

How "some printers can create different densities of toner dot" is
accomplished. Is that any clearer?

What mechanism is used to make the dot more or less dense? Is the toner
selective to certain types of charge, and only adhere partially, for
instance? Does the dot size alter?

How does a different density of toner get created for a specific dot?

Art
 
Arthur Entlich said:
I believe the question clearly related to your posting.

How "some printers can create different densities of toner dot" is
accomplished. Is that any clearer?

What mechanism is used to make the dot more or less dense? Is the
toner selective to certain types of charge, and only adhere partially,
for instance? Does the dot size alter?

How does a different density of toner get created for a specific dot?
Click to expand...

Is my suggestion of it involving the developer at all plausible? I've
looked at my manuals, and even the service manual which gives a detailed
breakdown of how the thing works, but I can't see a specific mention of
the method involved.

I believe newer models (CLC1160) have toner and developer combined but
my machine has them as separate items. Each colour's developer is
apparently good for about 40,000 pages, whereas the toner lasts about
5,000.
 
There's a simple test: Print some text at 2 pt. size. A 600 DPI printer will
print it barely readable but a 1200 DPI printer will produce readable
characters.
Click to expand...


Here's some 2-point text printed at
best quality (5760 x 1440) on an
Epson R1800, on photo paper. Dot
gain will limit results on any paper
surface that's not completely smooth.

The print was scanned at 4800 dpi,
then downsampled to 600.

<http://www.terrapinphoto.com/test011.jpg>


rafe b
www.terrapinphoto.com
 
Color laser uses a halftoning process, and does not deposit variable density
dots. AFAIK, dye-sub is the only process that actually does this.
Click to expand...


But dots can be (and are) modulated for width.

So, internally, the video bit stream to the
lasers is considered 4 bit/pixel -- ie.,
16 codes for each pixel's dot-width --
so long as the linear resolution is at
600 x 600 dpi.

This is independent of the halftoning or
error diffusion pattern.


rafe b
www.terrapinphoto.com
 
done?

Color laser uses a halftoning process, and does not deposit variable density
dots. AFAIK, dye-sub is the only process that actually does this.
Click to expand...

Not true. Color lasers deposit variable density dots. They also do
proprietary screening that's not directly related to conventional press
halftoning.

In summary, you can't really compare what any given laser engine is
doing directly with what happens on press.
 
Once again, I ask, how?

I can certainly see the dots varying in size, as the screen area
changes, but how is the density of the dot altered?

Is the electrostatic charge changed, so that more or less toner at a
specific location is attracted to the paper/drum or transfer belt?

I realize color laser printer use different screen methods than web or
other wet process ink presses.

Art
 
Arthur Entlich said:
I can certainly see the dots varying in size, as the screen area
changes, but how is the density of the dot altered?
Click to expand...

There is plenty of proprietary technology involved, but it involves
modulating the intensity of the laser.
 
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